1. Technical Field
The present invention relates to an image display system, an image display method, an information processing apparatus, an image display device, a control program, and a recording medium.
2. Related Art
There is known a projection system that includes a personal computer (hereinafter, referred to as PC) performing an image processing, such as shape correction or color correction of an video source, a projector projecting an image obtained through the image processing by the PC on a screen, and a serial cable, such as a USB (Universal Serial Bus) cable, connecting the PC and the projector for data transmission and reception (for example, see JP-A-2004-69996).
In the projector system described in JP-A-2004-69996, the image processing is primarily performed on the PC, and the projector simply projects the image, not performing a complex image processing. Accordingly, the configuration of the projector can be considerably simplified. Further, since the PC originally has a graphic processing function, a high definition image processing can be performed without adding a new function to the PC.
Here, for example, when the video source is a motion picture, if a transmission speed of the USB is low, it takes much time to transmit one image data. Then, a frame rate of a display image by the projector is delayed, and the motion picture is not appropriately played. For example, a frame rate of 30 frames/second is suitable for smoothly play the motion picture, but this frame rate cannot be realized at all to transmit the entire image data when the USB is used. While stable communication speed in the USB 2.0 is approximately 240 Mbps, when display resolution is XGA (1024×768 dots), the data quantity becomes approximately 25 Mbits in an image having color information of 30 bits per pixel. Then, the image data can be merely transmitted at a frame rate of 9 frames/second. Even though communication is temporarily performed at a theoretical maximum communication speed of 480 Mbps, a frame rate is nor more than 18 frames/second. Accordingly, this frame rate does not meet the play of the motion picture.
In the projection system described in JP-A-2004-699969, there is suggested a method that reduces the amount of required transmission data so as to keep a frame rate to an appropriate level by transmitting data with reduced resolution, compressing data and transmitting the compressed data, or transmitting differential data of previous screen data.
However, when the data is transmitted with reduced resolution or the data is compressed and transmitted, the image is degraded, and the projector cannot display a high-definition image.
Further, when the differential data is transmitted, there is a possibility that the reduction of the amount of the transmission data does not exhibit a sufficient effect according to the contents to be displayed. In particular when this method is used for the play of the motion picture having the frame rate as an important factor, a change in screen widely spreads for each frame, and thus a sufficient frame rate is not obtained.
Therefore, there is needed a technology that can smoothly perform the transmission of information and can realize a good image display state.